Socket cover and plug interlocking switch



Jan. 13, 1948. P. McSHANE ETAL 2,434,576

SOCKET COVER AND PLUG INTERLOCKING SWITCH Filed Aug. 2, 1945 5 Sheets-Sheet 1 WITNESSES:

ATTORNEY Jan. 13, 1948.

5 Sheets-Sheet 2 \Q. a Q

WITNESSES:

' 2&4, /%)%ZEZ Q SJ Jan. 13, 1948. P. M SHANE EI'AL SOCKET COVER AND PLUG INTERLOCKING SWITCH Filed Aug. 2, 1945 5 Sheets-Sheet 3 Jan. 13, 1948. P. McSHANE ETAL SOCKET COVER AND PLUG INTERLOCKING swmcn Filed Aug. 2, 1945 5 Sheets-Sheet 4 WITNESSES:

Jan. 13, 1948. P, MCSHANE ET AL SOCKET COVER AND PLUG INTEELCCKING SWITCH Filed Aug. 2, 1945 5 Sheets-Sheet 5 WITNESSES:

ATTOR Y Patented Jan. 13, 1948 SOCKET COVER AND PLUG INTERLOCKING SWITCH Phelan McShano and David E. Renshaw, Pitts burgh, Pa., asslgnors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation Pennsylvania Application August 2, 1945, Serial No. 608,585

Claims. (01. 200*50) voltage from being impressed on the contact members of the power center when they are being brought into contact or when being separated, thereby precluding the possibility of an arc being. formed and igniting explosive mixtures that may exist.

A further object of our invention is to provide protection against short circuits and overloads in the machines and power circuits connected to the power center.

Still another object of our invention is to provlde covers for the receptacles for the power cables which are so interlocked that operation of the power take-off devices is prevented unless either a connector is in each receptacle or its cover is in place.

A more general object of our invention is to provide an explosion-proof power center which is simple and efllcient in operation and which may be economically manufactured and installed.

Other objects of our invention wlllfbe explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment 'of our invention, the power center comprises two secmoving the power center.

at the receptacle end in order to encourage the tions, one of which contains receptacles for the connectors'for power cables. The other section is explosion-proof and contains positive and negative contactors, overload tripping mechanism and an interlocking device. Individual covers are provided for certain receptacles for use when one or more connectors are not inplace. The interlocking is such that when a connector is not in place a cover must be placed over the receptacle before the other connectors can be drawn down into contact with the terminals in the receptacles.

For a fuller understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a view, in end elevation, of a power center embodying our invention; 1

Fig. 2 is a view, in side elevation, of the power center shown in F181 1;

Fig. 3 is an enlarged view, in perspective, of the interior of a portion of the power center;

Fig. 4 is an enlarged view, in perspective, of the receptacle end of the power center;

Fig. 5 is an enlarged view, partially in elevation and partially in section, showing one of the interlocking devices'for the operating mechanism in the released position;

Fig. 6 is an enlarged view of a portion of the structure illustrated in Fig. 5, showing the interlocking device in the locked position;

Fig. 'I is an enlarged detailview of the interlocking device, and

Fig. 8 is a diagrammatic view of the electrical connections within the power center.

Referring to the drawings, and particularly to Figs. 1 and 2, the power centershown therein comprises two sections or compartments l0 and H. As shown most clearly in Fig, 1, the compartment I0 contains a plurality of receptacles designated by the reference numerals I to 4, inclusive, for receiving removable connectors for power cables. Thus, one of the receptacles may be utilized for the incoming line, one for a cable for supplying power to a cutting machine, one for a cable to a conveyor or loading machine and one for a coal drill.

The two sections Ill and H are bolted together at I! and mounted on a sled or skid l3 in order that the power center may be moved easily from one location to another in a mine. A suitable rope or chain may be attached to a hook M for The hook it is located disconnecting of thepower cables before the location of the power center is changed.

As shown more clearly in Fig. 3, the section or compartment II, the explosion-proof cover of which has been removed, contains two electromagnetic contactors l5 and l6,.an overload relay H, a control switch l8 and a reset push button is. As shown in the diagram in Fig. 8, the contactor H5 is connected to the positive terminal of the in coming line receptacle I, and the contactor I6 is connected to the negative terminal of the receptacle l. The actuating coils of these contactors are connected across the line terminals in seriescircuit relation with the contact members of the overload relay l1 and the control switch l8.

The overload relay I1 is provided with four series coils 2|, 22, 23 and 24. The coil2l is in the circuit for the receptacle 2, which, as explained hereinbefore, may be utilized for a cutting machine. The coil 22 is in the circuit for the receptacle 3, which may be utilized tor a conveyor,

and the coils 23 and 24 are connected in the circuit for the receptacle 4, which may be utilized for a drill.

The connections for the overload relay are such that should an overload occur in any one of the cables or machines connected to the receptacles, the relay will operate and interrupt the circuit to the actuating coils of the contactors |5 and I6. When the plunger 25 of the relay has once been raised by-the armature of any one of the series coils, it is latched in the raised position by a spring biased latch 26 and will remain in the raised position until released by the push button l9, which extends through the cover of the control compartment As shown most clearly in Figs. 3, 4 and 5, the cylindrical cover for the explosion-proof compartment H is attached by means of four heavy bolts 28, which are so located that it is necessary to remove all of the connectors from the receptacles in the compartment I and then withdraw the covers for the receptacles before access can be gained to all of the bolts 28. As shown in Fig. 5, an opening 29 is provided in the head of each bolt and a suitable wrench may be inserted into this opening when the cover and connector for the right receptacle are removed. Thus, it is apparent that the cover for the explosion-proof compartment cannot be removed if voltage is impressed on any part connected with the power center.

Each cable connector 30 is so constructed that it will fit into its proper receptacle and no other. A shown in Fig. 5, each connector is provided with a hinge pin 3|, which is of a different size from the other pins and may be inserted through an opening 32 of a corresponding size in a plate 33 for the receptacle compartment Ill. The connectors 30 are positively latched in place by a clamping device 34 to prevent the accidental withdrawal of a connector. The clamping device is moved inwardly and outwardly by a rotating screw 35 having a handle 36 which is readily accessible.

As shown in Figs. and 6, each connector is provided with a projection 31 which is inserted underneath a spring biased latch 38 after the hinge Din 3| is inserted in its proper place. The projection 31 may be inserted underneath the latch 38 by compressing an interlocking member 39 against the pressure of a spring 4 I.

As shown in Figs. 6 and 7, the interlocking members 39, one of which is provided for each receptacle, are disposed to cooperate with an interlocking collar 42, which is secured to the screw 35, to prevent the rotation of the screw unless either a connector or a receptacle cover plate 43 is in place in each receptacle as hereinafter explained. As shown in Fig. 4, the cover plates 43 are each provided with a projection 44 similar to the projections 31 on the connectors.

Referring again to Fig. '7, it will be seen that the collar 42 is provided with a rectangular portion 45 and a cylindrical portion 46. When the interlocking members 39 are in their uppermost position they engage the rectangular portion 45 to prevent rotation of the screw 35. Referring to Fig. 5, it will be seen that when all of the interlocking members 33 are depressed by the insertion of either the projection 31 of a connector or the projection 44 of a cover plate underneath the latches 38, the screw 35 may be rotated to move the clamping device inwardly to secure the connectors or the cover plates in their operating positions.

A spring 41 may be so disposed within the clamping device that it is compressed when the device is moved outwardly, thereby maintaining pressure on the connectors during the initial rotation of the screw 35 and also assisting in the overcoming of the friction between the contact members of the connectors and receptacles when the connectors are being inserted into position by operating the clamping device inwardly. The provision of the spring 41 is optional when contact members of the type shown are utilized.

An extension 48 may be attached to the inner end of the screw 35 by a coupling sleeve 49. As

shown in Fig. 3, the extension 48 extends into the contactor compartment ii to operate the control switch I8. The switch [8 is spring opened and stands open at all times except when the connectors or receptacle covers are firmly clamped down by rotating the screw 35 to its innermost position.

When the connectors are inserted, the control switch i8 remains open until the connectors are in their final contact position. When the connectors are being withdrawn, the control switch |B is opened by the first few turns of the screw 35 before the connectors are withdrawn sufliciently to open the circuit through their contact members. Thus, the energizing circuit for the actuating coils of the contactors I5 and 6 is interrupted by the opening of the switch l8 and these contactors open to deenergize the contact members of the outgoing cable receptacles before the connectors can be withdrawn from the receptacles or break contact with the stationary members shown in Fig. 4.

In addition to the foregoing electrical interlocking, mechanical interlocking is provided to prevent the release of the clamping device if either or both contactors fail to open when the control switch It! is opened. As shown in Fig. 3, the moving armatures of the contactors l5 and I6 are linked together by a rod 50 and these armatures are connected to a rocker 5| by links 52 and 53. The rocker 5| is pivoted at 54 and is provided with a keyhole slot 55 through which the inner end of the screw 35 passes.

When the contactors |5 and I6 are both open, the rocker 5| is actuated to a position in which the sleeve 49 on the screw 35 is free to pass through the enlarged portion of the opening 55. In this position the hand wheel 35 may be rotated to withdraw the screw 35 and the sleeve 48 through the opening 55.

If either one of the contactors has failed to open, the rocker 5| is in a position in which the shaft 35 is in the small portion of the keyhole opening 55 and the sleeve 49 cannot pass through this portion of the opening. Thus, the screw 35 cannot be withdrawn and the clamping device cannot be released to permit removal of the connectors. Therefore, it will be seen that the electrical and mechanical interlocking assure that an arc will not be drawn at the contact members of the receptacles and the connectors.

As explained hereinbeiore, an individual cover 43 is provided for each receptacle except the incoming line for use when one or more of the connectors are not in place. As shown in Fig. 5, each cover 43 is attached to the receptacle compartment by a hinge pin 56 which engages a hook 51 disposed inside the receptacle compartment. When the covers are not in use they slide into pockets in the receptacle compartment where they cannot be damaged.

As shown in Fig. 5, a spring 58 is disposed inside of a tube 59 on the top of the cover plate 43 and is compressed by a pin 8| when the cover. is inthat we have provided a control device which assures that voltage cannot be impressed on any contact members when they are being brought into engagement or when being separated, thereby precluding the possibility of an are being formed and igniting explosive mixtures that may exist in a mine or other place. Furthermore, the control device is so constructed that the cover for the explosion-proof compartment of the device cannot be removed if voltage is impressed on any part connected with the device.

Since numerous changes may be made in the above-described construction, and diflerent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, and means for attaching said cover to said receptacle compartment, said means being accessible for the removal of said cover only when all of said connectors are removed from the receptacles.

2. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, and means for attaching said cover to said receptacle compartment, said connectors preventing access to said means when they are in the receptacles.

3. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, and means disposed underneath said connectors for preventing removal of said cover while the connectors are in the receptacles.

4. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, cover plates for certain receptacles, clamping means for retaining a connector in or a cover plate over each receptacle, interlocking means controlling the operation of said clamping means, and means on said connectors and said cover plates for releasing said interlocking means.

5. A control device including a receptacle compartment having a plurality of connector receptacles therein arid a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle. cover plates for certain receptacles, clamping means for retaining a connector in or a cover'plate over each receptacle, and interlocking means for preventing the operation of said clamping means unless either a connector is in or a cover plate is over each receptacle.

6. A control deviceincluding a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, cover plates for certain receptacles, spring biased clamping means for retaining a connector in or a cover plate over each receptacle, and interlocking means for preventing the operation of said clamping means unless either a connector is in or a cover plate is over each receptacle, said connectors and said cover plates having fastening means thereon for releasing said interlocking means.

'7. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, cover plates for certain receptacles, clamping means for retaining a connector in or a cover plate over each receptacle, and interlocking means for preventing the operation or said clamping means unless either a connector is in or a cover plate is over each receptacle, said receptacle compartment having slots therein for receiving said cover plates, and spring means for biasing the cover plates outwardly from said compartment.

8. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attachedito the receptacle compartment, a cable connector for each receptacle, cover plates for certain receptacles, clamping means for retaining a connector in or a cover plate over each receptacle, interlocking means controlling the operation of said clamping means, means on said connectors and said cover plates for releasin said interlocking means, a controlswitch in the control compartment, and means on the clamping means 'for actuating said control switch when said connectors or cover plates are in their operating position.

9. A control device including a receptacle compartment having a plurality of connector receptacles therein and a control compartment comprising an explosion-proof cover removably attached to the receptacle compartment, a cable connector for each receptacle, cover plates for certain receptacles, clamping means for retaining a connector in or a cover plate over each receptacle, interlocking means controlling the operation of said clamping means, means on said connectors and said cover plates for releasing said interlocking means, switching means in the control compartment for establishing electrical circuits between said receptacles, a control switch for controlling the operation of said switching means, and means on the clamping means for actuating said control switch when said connectors or cover plates are in their operating positions.

10. A control device including a receptacle compreventing the releasing of said clamping means while said switching means are closed. PHELAN McSHANE.

DAVID E. RENSHAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,339,496 Madeira Jan. 18, 1944 1,347,345 Lofgren July 20, 1920 2,317,867 Chandler Apr. 27, 1943 

